For crops having heavy foliage, such as potatoes, tomatoes, sugar beets, beans, cabbage, broccoli, cotton, etc., it is commonly advisable to spray chemicals for the control of insects, diseases and weeds in such a way that the chemicals reach the underside of the leaves. This is a difficult problem for most sprayer designs. U.S. Pat. No. 2,770,501 discloses a mechanism which when used on a sprayer accomplishes coverage on the underside or leaves. The mechanism, however, has been inefficient and, consequently, not widely accepted.
U.S. Pat. No. 2,770,501 discloses use of a wing placed in a conduit through which air is forced. Oppositely, directed streams of liquid chemical are ejected into a triangular opening extending from top to bottom through the central part of the wing. The base portion of the triangular opening forms the leading edge of a second wing profile which extends rearwardly to conform to the profile of the larger primary wing profile. Although chemical trails rearwardly along the upper and lower surfaces of the wing, large droplets or amounts of chemical drop onto the ground in a stream and are not properly utilized.
U.S. Pat. No. 4,504,014 was directed to improving the spray pattern of this type of spray head. The wing was altered to have a rectangular opening, instead of a triangular opening and the grommet was given certain nozzle characteristics. These improvements helped decrease emission of large droplets or amounts of chemical being ejected. It has been found, however, that chemical continued to stream. Consequently, in the case of herbicides, a sprayed field tended to have rows where weeds had been killed and spaces between the rows where weeds continued to thrive.
The present invention further improves the devices of U.S. Pat. Nos. 2,770,501 and 4,504,014.